Sphingosine-1-phosphate receptor-2 regulates expression of smooth muscle alpha-actin after arterial injury.
Sphingosine-1-phosphate receptor-2 regulates expression of smooth muscle alpha-actin after arterial injury.
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DOI：
10.1161/atvbaha.109.191965
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发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Daum G
中科院分区：
文献类型：
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作者：
Grabski AD;Shimizu T;Deou J;Mahoney WM Jr;Reidy MA;Daum G
本研究验证了S1 P2 R调节动脉损伤后SMC分化基因表达的假设。颈动脉结扎损伤在野生型和S1 P2 R基因敲除小鼠中进行。在损伤后的不同时间点，通过定量PCR测量多个SMC分化基因、myocardin和S1 P受体（S1 P1 R、S1 P2 R和S1 P3 R）的表达。这些实验表明，在损伤后第7天，S1 P2 R特异性调节平滑肌α-肌动蛋白（SMA）的表达，并且这不是由心肌蛋白或任何S1 PR表达的变化介导的。使用野生型和S1 P2 R缺失小鼠制备的颈动脉SMC进行的体外研究表明，S1 P刺激所有受试SMC分化基因的表达，但S1 P2 R仅显著调节SMA和SM 22 α的表达。染色质免疫沉淀分析表明，S1 P诱导的血清应答因子的SMA启动子和增强子的募集在很大程度上取决于S1 P2 R。S1 P刺激的SMA表达需要依赖于S1 P2 R的RhoA激活和细胞内钙库的钙动员。螯合的钙不影响激活RhoA的S1 P，而封锁Rho的C3外毒素部分抑制钙的动员S1 P。本研究结果支持了S1 P2 R在损伤后调节SMA表达的假设。我们进一步得出结论，SMA的转录调控S1 P在体外需要S1 P2 R依赖的激活RhoA和动员钙从细胞内钙库。
This study tests the hypothesis that S1P2R regulates expression of SMC-differentiation genes following arterial injury. Carotid ligation injury was performed in wild-type and S1P2R-null mice. At various time points after injury, expression of multiple SMC differentiation genes, myocardin, and S1P receptors (S1P1R, S1P2R, and S1P3R) was measured by quantitative PCR. These experiments demonstrate that at day 7 after injury, S1P2R specifically regulates expression of smooth muscle α-actin (SMA) and that this is not mediated by changes in expression of myocardin or any of the S1PRs. In vitro studies using carotid SMCs prepared from wild-type and S1P2R-null mice show that S1P stimulates expression of all SMC-differentiation genes tested, but S1P2R significantly regulates expression of SMA and SM22α only. Chromatin immunoprecipitation assays suggest that S1P-induced recruitment of serum response factor to the SMA promoter and enhancer largely depends on S1P2R. S1P-stimulated SMA expression requires S1P2R-dependent activation of RhoA and mobilization of calcium from intracellular stores. Chelation of calcium does not affect the activation of RhoA by S1P, whereas blockade of Rho by C3 exotoxin partially inhibits the mobilization of calcium by S1P. The results of this study support the hypothesis that S1P2R regulates expression of SMA after injury. We further conclude that transcriptional regulation of SMA by S1P in vitro requires S1P2R-dependent activation of RhoA and mobilization of calcium from intracellular calcium stores.